Determining an endpoint of a planarization process

Abstract

A method for determining an endpoint of a planarization process comprising planarizing a substrate material using a functionalized chemical planarization pad. The functionalized chemical planarization pad includes a plurality of functional groups bonded to a material of the pad. The functional groups are configured, with or without the assistance of reagents in a solution, to chemically react with the substrate material such that a portion of substrate material bonds to the functional groups. One or more parameters of the substrate material and/or the planarization pad are monitored during the planarization process. The endpoint of the planarization process is determined based upon the one or more parameters of the substrate material and/or the planarization pad, and an indication is output that the endpoint is reached.

1 . A method for determining an endpoint of a planarization process, the method comprising:
 planarizing a substrate material using a functionalized chemical planarization pad, the functionalized chemical planarization pad including a plurality of functional groups bonded to a material of the pad, the functional groups, with or without the assistance of reagents in a solution, being configured to chemically react with the substrate material such that a portion of substrate material is removed at least in part by bonding to the functional groups;   monitoring one or more parameters of the substrate material and/or the planarization pad during the planarization process;   determining the endpoint of the planarization process based upon the one or more parameters of the substrate material and/or the planarization pad; and   outputting an indication that the endpoint is reached.   
     
     
         2 . The method of  claim 1 , wherein monitoring the one or more parameters comprises monitoring reflectance of the planarization pad. 
     
     
         3 . The method of  claim 2 , wherein monitoring the reflectance of the planarization pad comprises correlating the reflectance to an amount of the substrate material removed from a wafer. 
     
     
         4 . The method of  claim 1 , wherein monitoring the one or more parameters comprises tracking deposition of the substrate material on a mirror placed on a surface of the pad. 
     
     
         5 . The method of  claim 1 , wherein monitoring the one or more parameters comprises monitoring an optical spectrum of the planarization pad to detect appearance of a second material that underlies the substrate material. 
     
     
         6 . The method of  claim 1 , wherein monitoring one or more parameters comprises monitoring an infrared spectrum of the planarization pad. 
     
     
         7 . The method of  claim 1 , wherein monitoring the one or more parameters comprises monitoring friction between the substrate material and the pad. 
     
     
         8 . The method of  claim 7 , wherein determining the endpoint of the planarization process comprises detecting a change in friction between the substrate material and the pad. 
     
     
         9 . The method of  claim 1 , further comprising using the monitored one or more parameters of the pad to determine an endpoint of a pad use cycle. 
     
     
         10 . The method of  claim 1 , further comprising performing a regeneration process to remove a portion or all of the substrate material bound to the pad to thereby regenerate the pad, and monitoring the one or more parameters of the planarization pad to determine an endpoint of the regeneration process. 
     
     
         11 . The method of  claim 1 , wherein determining the endpoint of the planarization process comprises inputting the one or more parameters into an endpoint determination model to thereby cause the endpoint determination model to output the indication that the endpoint is reached. 
     
     
         12 . A planarization tool, comprising:
 a functionalized chemical planarization pad comprising a plurality of functional groups bonded to a material of the pad, the functional groups being configured to chemically react with a substrate material, with or without the assistance of reagents in a solution, such that a portion of substrate material bonds to the functional groups;   a substrate holding system configured to hold a substrate against the functionalized chemical planarization pad;   an optical monitoring system configured to monitor one or more optical parameters of the substrate material and/or the planarization pad during the planarization process; and   a computing system comprising one or more processors configured to determine the endpoint of the planarization process based upon the one or more optical parameters of the substrate material and/or the planarization pad, and output an indication that the endpoint is reached.   
     
     
         13 . The planarization tool of  claim 12 , wherein the optical monitoring system is configured to monitor reflectance of the planarization pad. 
     
     
         14 . The planarization tool of  claim 12 , wherein the optical monitoring system is configured to track deposition of the substrate material on a mirror placed on a surface of the pad. 
     
     
         15 . The planarization tool of  claim 12 , wherein the optical monitoring system is configured to monitor an optical spectrum of the planarization pad to detect appearance of a second material that underlies the substrate material. 
     
     
         16 . The planarization tool of  claim 12 , wherein the optical monitoring system is configured to monitor an infrared spectrum of the planarization pad. 
     
     
         17 . The planarization tool of  claim 12 , wherein the one or more processors are further configured to use the monitored one or more optical parameters of the pad to determine an endpoint of a pad use cycle. 
     
     
         18 . The planarization tool of  claim 12 , wherein the one or more processors are further configured to monitor the one or more optical parameters of the planarization pad to determine an endpoint of a pad regeneration process. 
     
     
         19 . The planarization tool of  claim 12 , wherein the one or more processors are further configured to input the one or more monitored optical parameters into an endpoint determination model to thereby cause the endpoint determination model to output the indication that the endpoint is reached. 
     
     
         20 . A planarization tool, comprising:
 a functionalized chemical planarization pad comprising a plurality of functional groups bonded to a material of the pad, the functional groups being configured to chemically react with a substrate material such that a portion of substrate material bonds to the functional groups;   a substrate holding system configured to hold a substrate against the functionalized chemical planarization pad;   a friction monitoring system configured to monitor friction between the substrate material and the pad; and   a computing system comprising one or more processors configured to,   determine the endpoint of the planarization process based upon detecting a change in friction between the substrate material and the pad, and   output an indication that the endpoint is reached.